Ethylene/CO Interpolymers for High-Speed Extrusion Adhesion

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Solution Overview

Problem

Conventional polymers used in extrusion coating lines experience unacceptable fiber tear adhesion at higher line speeds due to reduced oxidation time of molten polymer before contacting the paper substrate, leading to inferior adhesion between the polymer and paper.

Innovation Solution

Development of ethylene/CO interpolymers with specific properties, such as CO content and melting point relationships, formed through high-pressure free-radical polymerization, which enhance melt strength and adhesion to paper substrates at lower temperatures and higher line speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If higher line speeds are used in extrusion coating, then productivity is improved, but adhesion to paper substrate deteriorates due to reduced oxidation time of molten polymer

Engineering Contradiction:
Improveline speedVSAvoidadhesion
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the polymer by incorporating specific amounts of carbon monoxide (0.1-10 wt%) into the ethylene-based polymer structure. This compositional parameter change alters the polymer's oxidation characteristics and adhesion properties, enabling it to maintain good adhesion even at higher line speeds where oxidation time is reduced.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymer material by copolymerizing ethylene with carbon monoxide to form an ethylene/CO interpolymer. This composite material combines the desirable properties of both monomers, resulting in a polymer that exhibits improved adhesion and oxidation behavior suitable for high-speed extrusion coating applications.

Inventive Principle:
Principle #40Composite materials

2Use of energy by stationary object

If lower melt temperatures are used, then energy consumption is reduced, but adhesion to paper substrate deteriorates

Engineering Contradiction:
Improvemelt temperatureVSAvoidadhesion
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent changes the thermal parameters of the polymer by incorporating carbon monoxide, which lowers the melt temperature of the ethylene/CO interpolymer compared to conventional ethylene-based polymers. This parameter change enables the polymer to achieve adequate adhesion at lower melt temperatures, reducing energy consumption while maintaining bonding performance.

Inventive Principle:
Principle #35Parameter changes

3Strength

If higher CO content is incorporated into ethylene/CO interpolymer, then melt strength is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvemelt strengthVSAvoidpolymerization process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent optimizes the CO content parameter within a specific range (0.1-10 wt%) to achieve the desired melt strength. By defining this parameter range, the patent balances the benefit of improved melt strength with the complexity of the polymerization process, avoiding excessive CO levels that would require more complex process control while still achieving adequate performance.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The ethylene/CO interpolymers demonstrate improved melt strength and adhesion at lower temperatures, enabling successful fiber tear adhesion even at higher line speeds, thus addressing the adhesion issues faced with conventional polymers.

Implementation Method 1

This adhesion is related to the oxidation of the molten polymer as it exits the extrusion die, and before it comes in contact with the paper

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

a composition comprising an ethylene/CO interpolymer, formed from a high pressure, free-radical polymerization

Methodology Applied
Scientific EffectFree-radical polymerization: Photopolymerisation

Data Source

PatentEP3704167B1Ethylene/co interpolymers and processes to make the same
Publication Date: 2023.10.18 DOW GLOBAL TECHNOLOGIES LLC
  • EP3704167B1 patent drawingFigure 1~2
  • EP3704167B1 patent drawingFigure 3~4
  • EP3704167B1 patent drawing

AI summary

A composition comprising an ethylene/CO interpolymer, formed from a high pressure, free-radical polymerization, and wherein the ethylene/CO interpolymer has the following properties: a) a CO content from "greater than 0" weight percent to less than, or equal to, 10 weight percent CO (carbon monoxide), based on the weight of the interpolymer; and b) a melting point, Tm, in ºC that meets the following relationship: Tm (ºC) ≤601.4 * (Density in g/cc) - 452.5(ºC).